#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include "SHA1.h"

#undef BIG_ENDIAN_HOST

/****************
* Rotate a 32 bit integer by n bytes
*/
#if defined(__GNUC__) && defined(__i386__)
static inline u32 rol(u32 x, intptr_t n)
{
	__asm__("roll %%cl,%0"
		:"=r" (x)
		: "0" (x), "c" (n));
	return x;
}
#else
#define rol(x,n) ( ((x) << (n)) | ((x) >> (32-(n))) )
#endif

void sha1_init(SHA1_CONTEXT *hd)
{
	hd->h0 = 0x67452301;
	hd->h1 = 0xefcdab89;
	hd->h2 = 0x98badcfe;
	hd->h3 = 0x10325476;
	hd->h4 = 0xc3d2e1f0;
	hd->nblocks = 0;
	hd->count = 0;
}


/****************
* Transform the message X which consists of 16 32-bit-words
*/
void transform(SHA1_CONTEXT *hd, unsigned char *data)
{
	u32 a, b, c, d, e, tm;
	u32 x[16];

	/* get values from the chaining vars */
	a = hd->h0;
	b = hd->h1;
	c = hd->h2;
	d = hd->h3;
	e = hd->h4;

#ifdef BIG_ENDIAN_HOST
	memcpy(x, data, 64);
#else
	{
		intptr_t i;
		unsigned char *p2;
		for (i = 0, p2 = (unsigned char*)x; i < 16; i++, p2 += 4)
		{
			p2[3] = *data++;
			p2[2] = *data++;
			p2[1] = *data++;
			p2[0] = *data++;
		}
	}
#endif


#define K1  0x5A827999L
#define K2  0x6ED9EBA1L
#define K3  0x8F1BBCDCL
#define K4  0xCA62C1D6L
#define F1(x,y,z)   ( z ^ ( x & ( y ^ z ) ) )
#define F2(x,y,z)   ( x ^ y ^ z )
#define F3(x,y,z)   ( ( x & y ) | ( z & ( x | y ) ) )
#define F4(x,y,z)   ( x ^ y ^ z )


#define M(i) ( tm =   x[i&0x0f] ^ x[(i-14)&0x0f] \
	^ x[(i-8)&0x0f] ^ x[(i-3)&0x0f] \
	, (x[i&0x0f] = rol(tm,1)) )

#define R(a,b,c,d,e,f,k,m)  do { e += rol( a, 5 )     \
	+ f( b, c, d )  \
	+ k	      \
	+ m;	      \
	b = rol( b, 30 );    \
		} while(0)
	R(a, b, c, d, e, F1, K1, x[0]);
	R(e, a, b, c, d, F1, K1, x[1]);
	R(d, e, a, b, c, F1, K1, x[2]);
	R(c, d, e, a, b, F1, K1, x[3]);
	R(b, c, d, e, a, F1, K1, x[4]);
	R(a, b, c, d, e, F1, K1, x[5]);
	R(e, a, b, c, d, F1, K1, x[6]);
	R(d, e, a, b, c, F1, K1, x[7]);
	R(c, d, e, a, b, F1, K1, x[8]);
	R(b, c, d, e, a, F1, K1, x[9]);
	R(a, b, c, d, e, F1, K1, x[10]);
	R(e, a, b, c, d, F1, K1, x[11]);
	R(d, e, a, b, c, F1, K1, x[12]);
	R(c, d, e, a, b, F1, K1, x[13]);
	R(b, c, d, e, a, F1, K1, x[14]);
	R(a, b, c, d, e, F1, K1, x[15]);
	R(e, a, b, c, d, F1, K1, M(16));
	R(d, e, a, b, c, F1, K1, M(17));
	R(c, d, e, a, b, F1, K1, M(18));
	R(b, c, d, e, a, F1, K1, M(19));
	R(a, b, c, d, e, F2, K2, M(20));
	R(e, a, b, c, d, F2, K2, M(21));
	R(d, e, a, b, c, F2, K2, M(22));
	R(c, d, e, a, b, F2, K2, M(23));
	R(b, c, d, e, a, F2, K2, M(24));
	R(a, b, c, d, e, F2, K2, M(25));
	R(e, a, b, c, d, F2, K2, M(26));
	R(d, e, a, b, c, F2, K2, M(27));
	R(c, d, e, a, b, F2, K2, M(28));
	R(b, c, d, e, a, F2, K2, M(29));
	R(a, b, c, d, e, F2, K2, M(30));
	R(e, a, b, c, d, F2, K2, M(31));
	R(d, e, a, b, c, F2, K2, M(32));
	R(c, d, e, a, b, F2, K2, M(33));
	R(b, c, d, e, a, F2, K2, M(34));
	R(a, b, c, d, e, F2, K2, M(35));
	R(e, a, b, c, d, F2, K2, M(36));
	R(d, e, a, b, c, F2, K2, M(37));
	R(c, d, e, a, b, F2, K2, M(38));
	R(b, c, d, e, a, F2, K2, M(39));
	R(a, b, c, d, e, F3, K3, M(40));
	R(e, a, b, c, d, F3, K3, M(41));
	R(d, e, a, b, c, F3, K3, M(42));
	R(c, d, e, a, b, F3, K3, M(43));
	R(b, c, d, e, a, F3, K3, M(44));
	R(a, b, c, d, e, F3, K3, M(45));
	R(e, a, b, c, d, F3, K3, M(46));
	R(d, e, a, b, c, F3, K3, M(47));
	R(c, d, e, a, b, F3, K3, M(48));
	R(b, c, d, e, a, F3, K3, M(49));
	R(a, b, c, d, e, F3, K3, M(50));
	R(e, a, b, c, d, F3, K3, M(51));
	R(d, e, a, b, c, F3, K3, M(52));
	R(c, d, e, a, b, F3, K3, M(53));
	R(b, c, d, e, a, F3, K3, M(54));
	R(a, b, c, d, e, F3, K3, M(55));
	R(e, a, b, c, d, F3, K3, M(56));
	R(d, e, a, b, c, F3, K3, M(57));
	R(c, d, e, a, b, F3, K3, M(58));
	R(b, c, d, e, a, F3, K3, M(59));
	R(a, b, c, d, e, F4, K4, M(60));
	R(e, a, b, c, d, F4, K4, M(61));
	R(d, e, a, b, c, F4, K4, M(62));
	R(c, d, e, a, b, F4, K4, M(63));
	R(b, c, d, e, a, F4, K4, M(64));
	R(a, b, c, d, e, F4, K4, M(65));
	R(e, a, b, c, d, F4, K4, M(66));
	R(d, e, a, b, c, F4, K4, M(67));
	R(c, d, e, a, b, F4, K4, M(68));
	R(b, c, d, e, a, F4, K4, M(69));
	R(a, b, c, d, e, F4, K4, M(70));
	R(e, a, b, c, d, F4, K4, M(71));
	R(d, e, a, b, c, F4, K4, M(72));
	R(c, d, e, a, b, F4, K4, M(73));
	R(b, c, d, e, a, F4, K4, M(74));
	R(a, b, c, d, e, F4, K4, M(75));
	R(e, a, b, c, d, F4, K4, M(76));
	R(d, e, a, b, c, F4, K4, M(77));
	R(c, d, e, a, b, F4, K4, M(78));
	R(b, c, d, e, a, F4, K4, M(79));

	/* Update chaining vars */
	hd->h0 += a;
	hd->h1 += b;
	hd->h2 += c;
	hd->h3 += d;
	hd->h4 += e;
}


/* Update the message digest with the contents
* of INBUF with length INLEN.
*/
void sha1_write(SHA1_CONTEXT *hd, unsigned char *inbuf, size_t inlen)
{
	if (hd->count == 64) { /* flush the buffer */
		transform(hd, hd->buf);
		hd->count = 0;
		hd->nblocks++;
	}
	if (!inbuf)
		return;
	if (hd->count) {
		for (; inlen && hd->count < 64; inlen--)
			hd->buf[hd->count++] = *inbuf++;
		sha1_write(hd, NULL, 0);
		if (!inlen)
			return;
	}

	while (inlen >= 64) {
		transform(hd, inbuf);
		hd->count = 0;
		hd->nblocks++;
		inlen -= 64;
		inbuf += 64;
	}
	for (; inlen && hd->count < 64; inlen--)
		hd->buf[hd->count++] = *inbuf++;
}


/* The routine final terminates the computation and
* returns the digest.
* The handle is prepared for a new cycle, but adding bytes to the
* handle will the destroy the returned buffer.
* Returns: 20 bytes representing the digest.
*/

void sha1_final(SHA1_CONTEXT *hd)
{
	u32 t, msb, lsb;
	unsigned char *p;

	sha1_write(hd, NULL, 0); /* flush */;

	t = hd->nblocks;
	/* multiply by 64 to make a byte count */
	lsb = t << 6;
	msb = t >> 26;
	/* add the count */
	t = lsb;
	if ((lsb += hd->count) < t)
		msb++;
	/* multiply by 8 to make a bit count */
	t = lsb;
	lsb <<= 3;
	msb <<= 3;
	msb |= t >> 29;

	if (hd->count < 56) { /* enough room */
		hd->buf[hd->count++] = 0x80; /* pad */
		while (hd->count < 56)
			hd->buf[hd->count++] = 0;  /* pad */
	}
	else { /* need one extra block */
		hd->buf[hd->count++] = 0x80; /* pad character */
		while (hd->count < 64)
			hd->buf[hd->count++] = 0;
		sha1_write(hd, NULL, 0);  /* flush */;
		memset(hd->buf, 0, 56); /* fill next block with zeroes */
	}
	/* append the 64 bit count */
	hd->buf[56] = msb >> 24;
	hd->buf[57] = msb >> 16;
	hd->buf[58] = msb >> 8;
	hd->buf[59] = msb;
	hd->buf[60] = lsb >> 24;
	hd->buf[61] = lsb >> 16;
	hd->buf[62] = lsb >> 8;
	hd->buf[63] = lsb;
	transform(hd, hd->buf);

	p = hd->buf;
#ifdef BIG_ENDIAN_HOST
#define X(a) do { *(u32*)p = hd->h##a ; p += 4; } while(0)
#else /* little endian */
#define X(a) do { *p++ = hd->h##a >> 24; *p++ = hd->h##a >> 16;	 \
	*p++ = hd->h##a >> 8; *p++ = hd->h##a; } while(0)
#endif
	X(0);
	X(1);
	X(2);
	X(3);
	X(4);
#undef X
}
